This invention relates to prostheses in general, and specifically to a fixture assembly by which a prosthetic device may be laterally positioned and axially aligned with respect to a wearer, in any of a range of positions and alignments. The invention provides a range and ease of adjustability not present in the prior art.
Prostheses are typically attached to a wearer by the use of a socket on the wearer's stump. It is known to utilize a socket adaptor to permit the prosthesis to be pivoted to a desirable angle with respect to the socket, and/or to provide some range of lateral (in all horizontal directions) position adjustability as between the socket and the prosthesis. Both of these adjustments permit greater tolerances in the fabrication and mounting of a socket on a wearer.
Prior art socket adaptors have numerous shortcomings. For example, many cannot be adjusted without removing the socket from the wearer. Because sockets normally fit snugly on the wearer's stump, removal of the socket can be a time-consuming process, and can sometimes cause discomfort to the wearer. Moreover, in order to accurately and appropriately adjust the alignment and position of the prosthesis, the socket may have to be removed repeatedly.
Accordingly, a substantial amount of time and energy is involved in adjusting and aligning a prosthesis using known socket adaptors.
Additionally, prior art adaptors permit the prosthesis to be selectably shifted or positioned laterally with respect to the socket. Where bolt and nut assemblies are used to assemble the components of these adaptors, this lateral positioning is sometimes achieved by providing an oversized opening about the bolt. Within the confines of that opening, the prosthesis may be moved laterally prior to tightening the bolt, effectively allowing the wearer and/or the prosthetist to position the prosthesis at a selected location.
The range of lateral positioning provided by prior art devices is substantially limited, however, because of the typical circular shape of the oversized openings. Such a circular shape does not permit the prosthesis to be offset or shifted to its maximum forward/backward position simultaneously with its maximum side-to-side position. Accordingly, prior art adaptors must be carefully affixed to the socket, to ensure that the opening will accommodate the desired lateral positioning of the prosthesis with respect thereto.